Regarding CS, do NOT allow yourself to be intimidated by “coder boys” who’ve been living and breathing CS for many years. They WILL show off, make one-upping comments, hog discussion time, and sound like know it alls. Trust me - they don’t know it all. They likely have some bad habits, and some big gaps in their knowledge. Some of them will be too arrogant to pay careful attention to assignment details or prof instructions, too.
Don’t let them get you down. You can start with good habits and learning what your profs want you to know. In some ways, you’ll have an edge in the long run.